Sandia Cave Geology

Sandia Cave is located in the east wall of Las Huertas Canyon in Madera Limestone of Pennsylvanian age (circa 300 million years ago. (~300 MA). Look for the spiral staircase which marks the entrance near the top of the canyon wall..
Area Geology [from Wikipedia] The Sandia Mountains are a fault block range, on the eastern edge of the Rio Grande Rift Valley. The Sandias were uplifted in the last ten million years as part of the formation of the Rio Grande Rift. They form the eastern boundary of the Albuquerque Basin. The core of the range consists of Sandia granite, approximately 1.5 billion years old (there is also some metamorphic rock of age 1.7 billion years). This is topped by a relatively thin layer (approximately 300 feet/100 meters) of sedimentary rock (mostly limestone, and some sandstone) of Pennsylvanian age (circa 300 million years ago). Potassium-feldspar (K-spar) crystals embedded within the Sandia granite give the mountains their distinct pink color.
This view looking East from Placitas, NW of Sandia Peak, shows the layered Madera limestone on the top of the mountain just to the left of the center of the picture. Sandia Cave is located in Las Huertas canyon "just over the top" of the mountain.

Want to learn more about the rocks and geology of the Sandia Mountains? Carol Hill's lecture on UNM's Story of New Mexico as part of the UNM Osher Continuing Ed lectures now includes a short visit to Sandia Cave as part of a field trip.

Sandia Cave Geology & Location